Base station signal matching device for distributed antenna system

ABSTRACT

A base station signal matching device is a base station signal matching device mounted in a distributed antenna system for amplifying a received base station signal and transmitting the amplified base station signal to a user terminal. The base station signal matching device includes a first unit for generating first and second branch base station signals by using a power division function based on the base station signal, and transmitting the second branch base station signal to a third unit, and a second unit for matching the first branch base station signal to be suitable for signal processing of the distributed antenna system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-Part of International ApplicationNo. PCT/KR2014/013106, filed Dec. 31, 2014, and claims priority fromKorean Patent Application No. 10-2014-0194376 filed Dec. 30, 2014, thecontents of which are incorporated herein by reference in theirentireties.

BACKGROUND

1. Field

The inventive concept relates to a base station signal matching device,and more particularly, to a base station signal matching device formatching a base station signal transmitted from a base station to besuitable for a distributed antenna system.

2. Description of Related Art

A distributed antenna system is an example of a relay system forrelaying communication between base station and user terminals. Thedistributed antenna system is used in terms of service coverageextension of base station so as to provide mobile communication servicesto even shaded areas necessarily generated indoors or outdoors.

The distributed antenna system, based on a downlink path, receives abase station signal transmitted from a base station to perform signalprocessing, such as amplification, on the base station signal, and thentransmits the signal-processed base station signal to a user terminal ina service area. Also, the distributed antenna system, based on an uplinkpath, performs signal processing, such as amplification, on a terminalsignal transmitted from the user terminal and then transmits thesignal-processed terminal signal to the base station. The matching ofsignals transmitted/received between base stations and the distributedantenna system is essential to implement such a relay function.Conventionally, external base station signal matching devices were used.

A conventional external base station signal matching device includespassive elements including an attenuator for adjusting the power of abase station signal to convert the base station signal having a highpower level into an appropriate power level required in the distributedantenna system, a filter for dividing a duplexer type base stationsignal transmitted from a base station into a downlink and an uplink,and the like. The passive elements are very high-priced, and have largesizes. Therefore, it is difficult to miniaturize the passive elements.

Also, the attenuator is used in the conventional external base stationmatching device is a high-power attenuator capable of adjusting highpower of base stations, but passive intermodulation characteristics ofthe attenuator are not satisfactory. Therefore, when a high-power basestation signal is input to the distributed antenna system via thehigh-power attenuator on a downlink path, a passive intermodulationdistortion (PIMD) signal is generated, and a spurious signal is causedas the generated PIMD signal is input through an uplink path. Inaddition, a large amount of heat is generated in attenuation of thehigh-power attenuator. Therefore, the base station signal matchingdevice is damaged, and the lifespan of the base station signal matchingdevice is shortened.

SUMMARY

An embodiment of the inventive concept is directed to a base stationsignal matching device which can be mounted in a base station interfaceunit, etc. of a distributed antenna system, so that it is possible toreduce manufacturing cost of the distributed antenna system, minimizethe influence of a passive intermodulation distortion signal, andprevent the generation of heat.

According to an aspect of the inventive concept, there is provided abase station signal matching device included in a distributed antennasystem for amplifying a received base station signal and transmittingthe amplified base station signal to a user terminal, the base stationsignal matching device including: a first unit configured to generatefirst and second branch base station signals by using a power divisionfunction based on the received base station signal, and transmit thesecond branch base station signal to a third unit; and a second unitconfigured to match the first branch base station signal to be suitablefor signal processing of the distributed antenna system.

According to an exemplary embodiment, the first unit may include acoupler configured to generate the first and second branch base stationsignals by using the power division function through separating thereceived base station signal. Herein, a power ratio of the first andsecond branch base station signals may be corresponding to a couplingratio of the coupler.

According to an exemplary embodiment, the coupling ratio of the couplermay be variable.

According to an exemplary embodiment, a power level of the first branchbase station signal may be lower than a power level of the second branchbase station signal.

According to an exemplary embodiment, the second unit may include afirst filter configured to receive the first branch base station signal,and have a pass band corresponding to a service frequency band of thefirst branch base station signal; and a first variable attenuatorconfigured to adjust power of the first branch base station signal suchthat the first branch base station signal passing through the firstfilter has a power level suitable for signal processing of thedistributed antenna system.

According to an exemplary embodiment, the second unit may furtherinclude a first power detector configured to detect a power level of thefirst branch base station signal passing through the first filter.

According to an exemplary embodiment, the second unit may furtherinclude a test signal generator configured to generate a test signal fordetermining whether the distributed antenna system normally operates.

According to an exemplary embodiment, the distributed antenna system mayamplify a received user terminal signal and transmit the amplified userterminal signal to a base station. The second unit may include a secondvariable attenuator configured to adjust power of the user terminalsignal such that the user terminal signal has a power level suitable forsignal processing of the base station; and a second filter configured tohave a pass band corresponding to a service frequency band of the userterminal signal of which power is adjusted by the second variableattenuator.

According to an exemplary embodiment, the second unit may furtherinclude a second power detector configured to detect a power level ofthe user terminal signal of which power is adjusted by the secondvariable attenuator.

According to an exemplary embodiment, the third unit may terminate thesecond branch base station signal to a ground through an attenuator orisolator.

According to an exemplary embodiment, the third unit may include a meansfor removing heat generated in the termination of the second branch basestation signal.

According to an exemplary embodiment, the third unit may be modularizedseparately from the first unit and the second unit.

According to another aspect of the inventive concept, there is provideda base station interface unit constituting a distributed antenna systemfor amplifying a received base station signal and transmitting theamplified base station signal to a user terminal and comprising a basestation signal matching device as stated above.

According to embodiments of the inventive concept, the base stationsignal matching device is mounted t in the base station interface unitof the distributed antenna system, so that the manufacturing cost of thedistributed antenna system can be reduced without requiring a separateexternal device for signal matching with base stations.

Also, the base station signal matching device performs signal processingfor matching, based on a low-power signal branched from a base stationsignal, and, separately from the low-power signal, terminates ahigh-power signal by using a high-power attenuator, so that it ispossible to improve passive intermodulation characteristics and preventdamage of the device and reduction in lifespan of the device.

BRIEF DESCRIPTION OF THE FIGURES

Exemplary embodiments of the inventive concept will be more clearlyunderstood from the following detailed description taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a block diagram schematically showing a topology of adistributed antenna system to which a base station signal matchingdevice is to be applied according to an embodiment of the inventiveconcept.

FIG. 2 is a block diagram schematically showing some components of abase station interface unit shown in FIG. 1.

FIG. 3 is a block diagram schematically showing some components of abase station signal matching device shown in FIG. 2.

FIG. 4 is a diagram showing in detail the base station signal matchingdevice shown in FIG. 3.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the inventive concept will be described belowin more detail with reference to the accompanying drawings. Theinventive concept may, however, be embodied in different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure will bethorough and complete, and will fully convey the scope of the inventiveconcept to those skilled in the art. Throughout the disclosure, likereference numerals refer to like parts throughout the various figuresand embodiments of the inventive concept.

In description of the inventive concept, detailed explanation of knownrelated functions and constitutions may be omitted to avoidunnecessarily obscuring the subject manner of the inventive concept.Ordinal numbers (e.g. first, second, etc.) are used for descriptiononly, assigned to the elements in no particular order, and shall by nomeans specify the name of the pertinent element or restrict the claims.

It will be understood that when an element is “connected” or “coupled”to another element, the element may be directly connected or coupled toanother element, and there may be an intervening element between theelement and another element. To the contrary, it will be understood thatwhen an element is “directly connected” or “directly coupled” to anotherelement, there is no intervening element between the element and anotherelement.

In the entire specification, when a certain portion “includes” a certaincomponent, this indicates that the other components are not excluded,but may be further included unless specially described. The terms“unit”, “-or/er” and “module” described in the specification indicate aunit for processing at least one function or operation, which may beimplemented by hardware, software and a combination thereof.

It is noted that the components of the inventive concept are categorizedbased on each main function that each component has. Namely, two or morethan two component units, which will be described below, may be combinedinto one component unit or one unit may be classified into two or morethan two component units for each function. Each of the component units,which will be described below, should be understood to additionallyperform part or all of the functions that another component has, inaddition to the main function that the component itself has, and inaddition, part of the functions that each component unit has may beexclusively performed by another component unit.

Hereinafter, embodiments of the inventive concept will be described indetail with reference to the accompanying drawings.

FIG. 1 is a block diagram schematically showing a topology of adistributed antenna system to which a base station signal matchingdevice is to be applied according to an embodiment of the inventiveconcept.

Referring to FIG. 1, the distributed antenna system DAS amplifies a basestation signal and then transmits the amplified base station signal to auser terminal (not shown), and amplifies a user terminal signal and thentransmits the amplified user terminal signal to a base station, therebyimplementing a relay function. In order to implement the relay function,the distributed antenna system DAS may include a base station interfaceunit 10 and a main unit 20, which constitute a headend node, anextension unit 30 that is an extension node, and a plurality of remoteunits 40 and 50 respectively disposed at remote service locations. Thedistributed antenna system DAS may be implemented as an analogdistributed antenna system or a digital distributed antenna system. Whennecessary, the distributed antenna system DAS may be implemented as ahybrid of the analog distributed antenna system and the digitaldistributed antenna system (i.e., performance of analog processing onsome nodes and digital processing on the other nodes).

However, FIG. 1 illustrates an example of the topology of thedistributed antenna system DAS, and the distributed antenna system DASmay have various topologies in consideration of particularity of itsinstallation area and application field (e.g., in-building, subway,hospital, stadium, etc.). As such, the number of the base stationinterface unit 10, the main unit 20, the extension unit 30, and theremote units 40 and 50 and upper/lower end connection relations betweenthe base station interface unit 10, the main unit 20, the extension unit30, and the remote units 40 and 50 may also be different from those ofFIG. 1. In the distributed antenna system DAS, the extension unit 30 isused when the number of branches to be branched in a star structure fromthe main unit 20 is limited as compared with the number of remote unitsrequired to be installed. Therefore, the extension unit 30 may beomitted when only the single main unit 20 sufficiently covers the numberof remote units 40 and 50 required to be installed, when a plurality ofmain units 20 are installed, or the like.

Each node and its function in the distributed antenna system DAS will bedescribed in detail. First, the base interface unit 10 may perform aninterface function between a base station and the main unit 20 in thedistributed antenna system DAS. In FIG. 1, it is illustrated that aplurality of base stations (first to nth base stations) (n is a naturalnumber of 2 or more) are connected to the single base station interfaceunit 10. However, the base station interface unit 10 may be separatelyprovided for each provider, each frequency band, or each sector.

In general, a radio frequency (RF) signal transmitted to a base stationis a signal of high power. Therefore, the base station interface unit 10may convert the RF signal of high power into a signal of power suitableto be processed in the main unit 20, and perform a function oftransmitting the power-adjusted RF signal to the main unit 20.

As shown in FIG. 1, when the base station interface unit 10 decreaseshigh power of an RF signal for each frequency band (or each provider oreach sector) to low power and then transmits, in parallel, the RFsignals of low power to the main unit 20, the main unit 20 may perform afunction of combining the low-power RF signals and distributing thecombined signal to the remote units 40 and 50. In this case, when thedistributed antenna system DAS is implemented as the digital distributedantenna system, the base station interface unit 10 may digitizelow-power RF signals and transmit, in parallel, the digitized low-powerRF signals to the main unit 10. The main unit 20 may combine thedigitized low-power RF signals, perform predetermined signal processingon the combined signal, and then distribute the signal-processed signalto the remote units 40 and 50. Alternatively, the main unit 20 maydigitize low-power RF signals transmitted from the base stationinterface unit 10, combine the digitized low-power RF signals, performpredetermined signal processing on the combined signal, and thendistribute the signal-processed signal to the remote units 40 and 50.

According to an implementation method, the base station interface unit10, unlike as shown in FIG. 1, may combine an RF signal for eachfrequency band (or each provider or each sector) and then transmit thecombined signal to the main unit 20. The main unit 20 may perform afunction of distributing the combined signal to the remote units 40 and50. In this case, when the distributed antenna system DAS is implementedas the digital distributed antenna system, the base station interfaceunit 10 may be separated into a unit for performing a function ofconverting a high-power RF signal into a low-power RF signal, a unit forconverting a low-power RF signal into an intermediate frequency (IF)signal, performing digital signal processing on the converted IF signal,and then combining the digital signal processed signal, and the like.Alternatively, when the distributed antenna system DAS is implemented asthe analog distributed antenna system, the base station interface unit10 may be separated into a unit for performing a function of decreasinghigh power of an RF signal to low power and a unit for combining a lowpower RF signal.

The base station signal matching device according to the embodiment ofthe inventive concept is mounted in the base station interface unit 10,to adjust the power level of a high-power RF signal transmitted from abase station. The base station signal matching device according to theembodiment of the inventive concept may be provided for each frequencyband (or each provider or each sector) in the base station interfaceunit 10. This will be described in detail below with reference to FIGS.2 to 4.

Each of the remote units 40 and 50 may separate the combined signaltransmitted from the main unit 20 for each frequency band and performsignal processing (analog signal processing in the analog DAS anddigital signal processing in the digital DAS) such as amplification.Accordingly, each of the remote units 40 and 50 can a base stationsignal to a user terminal in its own service coverage through a serviceantenna (not shown).

Meanwhile, in FIG. 1, it is illustrated that a base station BTS and thebase station interface unit 10 are connected to each other through an RFcable, the base station interface unit 10 and the main unit 10 areconnected to each other through an RF cable, and all units from the mainunit 20 to a lower end thereof are connected to each other throughoptical cables. However, a signal transport medium between nodes may bevariously modified.

As an example, the base station interface unit 10 and the main unit 20may be connected through an RF cable, but connected through an opticalcable or a digital interface. As another example, at least one ofconnection between the main unit 20 and the extension unit 30,connection between the main unit 20 and the remote unit 40 andconnection between the extension unit 30 and the remote unit 50 may beimplemented through an RF cable, a twist cable, a UTP cable, etc., aswell as the optical cable.

Hereinafter, this will be described based on FIG. 1. Therefore, in thisembodiment, the main unit 20, the extension unit 30, and the remoteunits 40 and 50 may include an optical transceiver module fortransmitting/receiving optical signals through electro-opticconversion/photoelectric conversion. When connection between nodes isimplemented through a single optical cable, the main unit 20, theextension unit 30, and the remote units 40 and 50 may include awavelength division multiplexing (WDM) element.

The distributed antenna system DAS may be connected, through a network,an external management device (not shown), e.g., a network managementserver or system (NMS). Accordingly, a manager can remotely monitor astatus and problem of each node in the distributed antenna system andremotely control an operation of each node through the NMS.

FIG. 2 is a block diagram schematically showing some components of thebase station interface unit shown in FIG. 1.

Referring to FIG. 2, the base station interface unit 10 may includefirst to nth base station signal matching devices 100_1 to 100_n eachcoupled to a corresponding base station among first to nth base stationsBTS_1 to BTS_n, and first to nth signal processing devices 200_1 to200_n each coupled to a corresponding base station signal matchingdevice among the first to nth base station signal matching devices 100_1to 100_n. In FIG. 2, it is illustrated that the first to nth signalprocessing devices 200_1 to 200_n transmit base station signals havingservice frequency bands distinguished from each other, and the first tonth base station signal matching devices 100_1 to 100_n and the first tonth signal processing devices 200_1 to 200_n are provided in the basestation interface unit 10, corresponding to the respective first to nthbase stations BTS_1 to BTS_n. However, it will be apparent that, asdescribed above, the first to nth base station signal matching devices100_1 to 100_n and the first to nth signal processing devices 200_1 to200_n may be provided in the base station interface unit 10 for eachsector or each provider.

Each of the first to nth base station signal matching devices 100_1 to100_n, based on a downlink path, may receive a base station signal inputfrom a corresponding base station. The base station signal may be an RFtype signal and have high power. Each of the first to nth base stationsignal matching devices 100_1 to 100_n may adjust the power level of thecorresponding base station signal to be suitable for the power levelrequired in the distributed antenna system (more specifically, a signalprocessing device, a main unit, etc., connected to a rear end of thebase station signal matching device), and transmit the base stationsignal of which power level is adjusted to a corresponding signalprocessing device.

Each of the first to nth signal processing devices 200_1 to 200_n, basedon a downlink path, may perform signal processing, such asamplification, on the transmitted base station signal, and then transmitthe signal-processed base station signal to the main unit 20 (see FIG.1). In this case, when the distributed antenna system is configured asthe digital distributed antenna system, the first to nth signalprocessing devices 200_1 to 200_n may digitize RF type base stationsignals subjected to signal processing such as amplification andtransmit the digitized base station signals to the main unit 20 (seeFIG. 1).

Meanwhile, although not shown in FIG. 2, the base station interface unit10 may further include a combining/distributing unit. Thecombining/distributing unit may combine output signals of the first tonth signal processing devices 200_1 to 200_n and transmit the combinedsignal to the main unit 20 (see FIG. 1).

Each of the first to nth signal processing devices 200_1 to 200_n, basedon an uplink path, may perform signal processing, such as amplification,on a user terminal signal which is transmitted from the main unit 20(see FIG. 1) and has a corresponding service frequency, and thentransmit the signal-processed user terminal signal to a correspondingbase station signal matching device. In this case, when the distributedantenna system is configured as the digital distributed antenna system,each of the first to nth signal processing devices 200_1 to 200_n mayconvert a digital type user terminal signal into an analog type signal,perform signal processing, such as amplification, on the convertedanalog type signal, and then transmit the signal-processed signal to thecorresponding base station signal matching device.

Meanwhile, although not shown in FIG. 2, when the base station interfaceunit 10 includes the above-described combining/distributing unit, thecombining/distributing unit may separate, for each service frequencyband, a signal which is transmitted from the main unit 20 (see FIG. 1)and obtained by combining user terminal signals, and transmit theseparated user terminal signals to the respective corresponding signalprocessing devices.

Each of the first to nth base station signal matching devices 100_1 to100_n, based on an uplink path, may adjust the transmitted user terminalsignal to be suitable for the power level required in the correspondingbase station and transmit the adjusted user terminal signal to the basestation.

FIG. 3 is a block diagram schematically showing some components of abase station signal matching device shown in FIG. 2. FIG. 4 is a diagramshowing in detail the base station signal matching device shown in FIG.3. The base station signal matching device shown in FIGS. 3 and 4 may beany one of the first to nth base station signal matching devices 100_1to 100_n shown in FIG. 2. Hereinafter, for convenience of illustration,the base station signal matching device will be described with referenceto FIGS. 3 and 4 together with FIG. 2, and descriptions overlapping withFIG. 2 will be omitted.

Referring to FIGS. 2 to 4, the base station signal matching device 100may include a power level adjusting unit 110, a signal matching unit130, and a termination unit 150.

The power level adjusting unit 110, based on a downlink path, maygenerate first and second branch base station signals of which powerlevels are adjusted based on an input base station signal. The powerlevel adjusting unit 110, for example, may include a coupler, andgenerate the first and second branch base station signals of which powerlevels are adjusted by using a power division function as the inputsignal is separated by the coupler. The power ratio the of first andsecond branch base station signals may correspond to a coupling ratio ofthe coupler. The coupling ratio of the coupler may be varied dependingon power levels required in the first and second branch base stationsignals.

The power level adjusting unit 110, based on a downlink path, maytransmit the first branch base station signal to the signal matchingunit 130 and transmit the second branch base station signal to thetermination unit 150. Here, the power level of the first branch basestation signal may be lower than that of the second branch base stationsignal.

The power level adjusting unit 110, based on the uplink path, mayperform coupling on a user terminal signal transmitted from the signalmatching unit 130 and transmit the coupled user terminal signal to thebase station BTS (see FIG. 1).

The signal matching unit 130, based on the downlink path, may receivethe first branch base station signal that have a relatively low power ascompared with the second branch base station signal, and match the firstbranch base station signal to be suitable for signal processing of thedistributed antenna system. For example, the signal matching unit 130may match the first branch base station signal in a manner that adjuststhe power level of the first branch base station signal to be suitablefor signal processing in the signal processing device 200, the main unit20 (see FIG. 1), etc., connected to the rear end of the base stationsignal matching device 100.

The signal matching unit 130, based on the downlink path, may include afirst filter 131 and a variable attenuator 133. The first filter 131 mayreceive the first branch base station signal. In this case, the firstfilter 131 may have a pass band corresponding to the service frequencyband of the first branch base station signal. Meanwhile, the firstfilter 131 may be implemented, as one duplexer, together with thefollowing second filter 132. The first variable attenuator 133 mayadjust the power of the first branch base station signal passing throughthe first filter 131 to have power of a level suitable for signalprocessing of the signal processing device 200, etc.

The signal matching unit 130, based on the downlink path, may furtherinclude a first power detector 135. The first power detector 135 maydetect the power level of the first branch base station signal passingthrough the first filter 131. Accordingly, the power level of the firstbranch base station signal can be monitored on the downlink path, and amanager can check (or identify) a status of the base station signalmatching device 100 at an installation spot of the base station signalmatching device 100 or a remote place through the NMS, based on themonitored power level. Meanwhile, according to an implementationexample, the first power detector 135 may detect the power level of thefirst branch base station signal of which power level is adjusted by thefirst variable attenuator 133 at the rear end of the first variableattenuator 133.

The signal matching unit 130, based on the downlink path, may furtherinclude a test signal generator 137. When the distributed antenna systemhaving the base station signal matching device 100 mounted therein isinitially installed, the test signal generator 137 may generate a testsignal for testing the distributed antenna system. The test signalgenerator 137 may transmit the test signal to the first variableattenuator 133 through the downlink path. The test signal may correspondto the first branch base station signal. In the distributed antennasystem having the base station signal matching device 100 mountedtherein, the integrity of the distributed antenna system can beidentified by diagnosing whether signal processing on the downlink pathis abnormal through the test signal.

The signal matching unit 130, based on the uplink path, may match a userterminal signal transmitted from the signal processing device 200 to besuitable for signal processing of the base station. For example, thesignal matching unit 130 may match the user terminal signal in a mannerthat adjusts the power level of the user terminal signal to correspondto the power level required in the base station BTS (see FIG. 2).

The signal matching unit 130, based on the uplink path, may include asecond filter 132 and a second variable attenuator 134. First, thesecond variable attenuator 134 may adjust the power level of a userterminal signal to be suitable for signal processing of the basestation. The second filter 132 may receive the user terminal signal ofwhich power level is adjusted by the second variable attenuator 134, andhave a pass band corresponding to the service frequency band of the userterminal signal.

The signal matching unit 130, based on the uplink path, may furtherinclude a second power detector 136. Accordingly, the power level of theuser terminal signal can be monitored on the uplink path, and a managercan check (or identify) a status of the base station signal matchingdevice 100 at an installation spot of the base station signal matchingdevice 100 or a remote place through the NMS, based on the monitoredpower level.

The termination unit 150, based on the downlink path, may receive thesecond branch base station signal that has a relatively high power ascompared with the first branch base station signal, and terminate thesecond branch base station signal to a ground. The termination unit 150may include a termination circuit 151, e.g., a high-power attenuator, anisolator, etc., and may terminate the second branch base station signalto the ground through the termination circuit 151.

The termination unit 150 may further include a means 153 for removingheat generated in the termination of the second branch base stationsignal (e.g., when the termination circuit 151 is configured as anattenuator to attenuate the second branch base station signal). Themeans 153 may be configured as a fan.

Meanwhile, according to an implementation example, the termination unit150 may be modularized separately from the power level adjusting unit110 and the signal matching unit 130. For example, in the base stationsignal matching device 100, the termination unit 150 may be modularizedto be physically separated from a module including the power leveladjusting unit 110 and the signal matching unit 130. According toanother implementation example, the termination unit 150 may bephysically separated as a separate device from the base station signalmatching device 100.

As described above, the base station signal matching device 100 ismounted in the base station interface unit 10 of the distributed antennasystem, so that the manufacturing cost of the distributed antenna systemcan be reduced without requiring a separate external device for signalmatching with base stations in the design and manufacturing of thedistributed antenna system.

Also, the base station signal matching device 100 separates a basestation signal into a low-power first branch base station signal and ahigh-power second branch base station signal, and terminates thehigh-power second branch base station signal by using the terminationunit separated from a configuration for processing the low-power firstbranch base station signal, so that it is possible to prevent, inadvance, the generation of an unnecessary wave as a passiveintermodulation distortion signal is input through the uplink path whena high-power signal is attenuated in the existing base station signalmatching device. In addition, the means for removing heat is provided inthe termination unit 150, so that it is possible to prevent thegeneration of heat caused by the attenuation of a high-power signal.Thus, it is possible to maximize the lifespan of the base station signalmatching device.

Also, the base station signal matching device 100 can monitor whetherthe device is abnormal by sensing, in real time, power levels of thedownlink path and uplink path in the signal matching unit 130, anddetermine whether the distributed antenna system is abnormal through atest signal in initial setting. Thus, it is possible to ensure theservice reliability of the distributed antenna system.

Meanwhile, in the above, the case where the base station signal matchingdevice according to the embodiment of the inventive concept is mountedin the base station interface unit of the distributed antenna system hasbeen described as an example with reference to FIGS. 1 to 4, but theinventive concept is not limited thereto. It will be apparent that thebase station signal matching device according to the embodiment of theinventive concept may be mounted in various communication devicesrequired to interface with other base stations.

While the inventive concept has been described with respect to thespecific embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the inventive concept as defined in thefollowing claims.

What is claimed is:
 1. A base station signal matching device included ina distributed antenna system for amplifying a received base stationsignal and transmitting the amplified base station signal to a userterminal, the base station signal matching device comprising: a firstunit configured to generate first and second branch base station signalsby using a power division function based on the received base stationsignal, and transmit the second branch base station signal to a thirdunit; and a second unit configured to match the first branch basestation signal to be suitable for signal processing of the distributedantenna system.
 2. The base station signal matching device of claim 1,wherein the first unit includes a coupler configured to generate thefirst and second branch base station signals by using the power divisionfunction through separating the received base station signal, wherein apower ratio of the first and second branch base station signals iscorresponding to a coupling ratio of the coupler.
 3. The base stationsignal matching device of claim 2, wherein the coupling ratio of thecoupler is variable.
 4. The base station signal matching device of claim1, wherein a power level of the first branch base station signal islower than a power level of the second branch base station signal. 5.The base station signal matching device of claim 1, wherein the secondunit includes: a first filter configured to receive the first branchbase station signal, and have a pass band corresponding to a servicefrequency band of the first branch base station signal; and a firstvariable attenuator configured to adjust power of the first branch basestation signal such that the first branch base station signal passingthrough the first filter has a power level suitable for signalprocessing of the distributed antenna system.
 6. The base station signalmatching device of claim 5, wherein the second unit further includes afirst power detector configured to detect a power level of the firstbranch base station signal passing through the first filter.
 7. The basestation signal matching device of claim 5, wherein the second unitfurther includes a test signal generator configured to generate a testsignal for determining whether the distributed antenna system normallyoperates.
 8. The base station signal matching device of claim 1, whereinthe distributed antenna system amplifies a received user terminal signaland transmits the amplified user terminal signal to a base station, andwherein the second unit includes: a second variable attenuatorconfigured to adjust power of the user terminal signal such that theuser terminal signal has a power level suitable for signal processing ofthe base station; and a second filter configured to have a pass bandcorresponding to a service frequency band of the user terminal signal ofwhich power is adjusted by the second variable attenuator.
 9. The basestation signal matching device of claim 8, wherein the second unitfurther includes a second power detector configured to detect a powerlevel of the user terminal signal of which power is adjusted by thesecond variable attenuator.
 10. The base station signal matching deviceof claim 1, wherein the third unit terminates the second branch basestation signal to a ground through an attenuator or isolator.
 11. Thebase station signal matching device of claim 10, wherein the third unitincludes a means for removing heat generated in the termination of thesecond branch base station signal.
 12. The base station signal matchingdevice of claim 1, wherein the third unit is modularized separately fromthe first unit and the second unit.
 13. A base station interface unitconstituting a distributed antenna system for amplifying a received basestation signal and transmitting the amplified base station signal to auser terminal, the base station interface unit comprising: at least onebase station signal matching device, wherein the base station signalmatching device including: a first unit configured to generate first andsecond branch base station signals by using a power division functionbased on the received base station signal, and transmit the secondbranch base station signal to a third unit; and a second unit configuredto match the first branch base station signal to be suitable for signalprocessing of the distributed antenna system.